This invention relates to the operation of an electro-magnetic indicator element used either alone, in small groups or as part of a large display.
No search has been performed prior to the filing of this application and the closest, prior art known to applicant is constituted by applicant's prior patents recited below.
Such indicator elements are each designed to selectively display one of two contrastingly coloured faces so that information may be displayed or "written" by the array, by the combined visual effects of the faces displayed by the individual elements.
Such rotatably mounted elements carry magnets and their orientation is controlled by a magnetizable member or pole piece, the sense of whose magnetization is determined by a winding and whose magnetic field controls the orientation of the corresponding element in accord with the sense of magnetization.
Electromagnetic elements of the type referred to are shown in U.S. Pat. Nos. 3,469,258 dated Sept. 23, 1969; 3,975,728 dated Aug. 17, 1976; 3,140,553 dated July 14, 1964; 3,624,941 dated Dec. 7, 1971; 3,365,824 dated Jan. 30, 1968; 3,295,238 dated Jan. 3, 1967; 3,303,494 dated Feb. 7, 1967; 3,754,245 dated Aug. 21, 1973; although the practical value of the invention described herein will be of more value in connection with the devices of some of these patents, than others.